\\[-1.8ex] Soil Heterogeneity & $-$0.110$^{***}$ & $-$0.102$^{***}$ & $-$0.093$^{***}$ & $-$0.086$^{***}$ & $-$0.063$^{***}$ & $-$0.062$^{***}$ \\ 
  & (0.040) & (0.032) & (0.031) & (0.032) & (0.022) & (0.021) \\ 
\\[-1.8ex] 
Oster $\delta$ for $\beta=0$ &  & 6.46 & 4.32 & 3.47 & 2.30 & 2.22 \\ 
Observations & 23,443 & 23,443 & 23,443 & 23,443 & 23,443 & 23,381 \\ 
R$^{2}$ & 0.009 & 0.359 & 0.374 & 0.377 & 0.405 & 0.409 \\ 
